Meziantou.Xunit.v3.ParallelTestFramework 1.0.6

By default, xUnit runs all test cases in a test class synchronously. This package extends the default test framework to execute tests in parallel.

For xUnit v3:

dotnet add package Meziantou.Xunit.v3.ParallelTestFramework

For xUnit v2:

dotnet add package Meziantou.Xunit.ParallelTestFramework

By default, all tests will run in parallel. Selectively disable parallelization by adding the DisableParallelization attribute to a collection or theory.

// All tests are run in parallel
public class ParallelTests
{
    [Fact]
    public void Test1() => Thread.Sleep(2000);

    [Fact]
    public void Test2() => Thread.Sleep(2000);

    [Theory]
    [InlineData(0), InlineData(1), InlineData(2)]
    public void Test3(int value) => Thread.Sleep(2000);

    // This test runs in parallel with other tests
    // However, its test cases are run sequentially
    [Theory]
    [DisableParallelization]
    [InlineData(0), InlineData(1), InlineData(2)]
    public void Test4(int value) => Thread.Sleep(2000);
}

// This collection runs in parallel with other collections
// However, its tests cases are run sequentially
[DisableParallelization]
public class SequentialTests
{
    [Fact]
    public void Test1() => Thread.Sleep(2000);

    [Fact]
    public void Test2() => Thread.Sleep(2000);
}

Previous versions of this package relied on built in xUnit attributes instead of exposing a dedicated DisableParallelization attribute. For backwards compatibility, parallelization can also be disabled by adding an explicit Collection attribute or Theory attribute with DisableDiscoveryEnumeration enabled.

// All tests are run in parallel
public class ParallelTests
{
    [Fact]
    public void Test1() => Thread.Sleep(2000);

    [Fact]
    public void Test2() => Thread.Sleep(2000);

    [Theory]
    [InlineData(0), InlineData(1), InlineData(2)]
    public void Test3(int value) => Thread.Sleep(2000);

    // This test runs in parallel with other tests
    // However, its test cases are run sequentially because of DisableDiscoveryEnumeration
    [Theory]
    [MemberData(nameof(GetData), DisableDiscoveryEnumeration = true)]
    public void Test4(int value) => Thread.Sleep(2000);

    public static TheoryData<int> GetData() =>  new() { { 0 }, { 1 } };
}

// This collection runs in parallel with other collections
// However, its tests cases are run sequentially because the Collection is explicit
[Collection("Sequential")]
public class SequentialTests
{
    [Fact]
    public void Test1() => Thread.Sleep(2000);

    [Fact]
    public void Test2() => Thread.Sleep(2000);
}

The code is greatly inspired by the sample from Travis Mortimer: https://github.com/xunit/xunit/issues/1986#issuecomment-831322722

{
  "$schema": "https://xunit.net/schema/current/xunit.runner.schema.json",
  "preEnumerateTheories": true
}

Parallel in a collection

Using the EnableParallelizationAttribute on an ICollectionFixture<T> enables the parallel execution between classes in a collection. If you want to enable parallisation inside a class you still need to add the EnableParallelizationAttribute on the test class aswell.

[CollectionDefinition("MyFixture Collection")]
[EnableParallelization] // This enables the parallel execution of classes in a collection 
public class MyFixtureCollection : ICollectionFixture<MyFixture>
{
}

[Collection("MyFixture Collection")]
public class MyFirstTestClass
{
    private readonly MyFixture fixture;

    public ParallelCollectionMultiClass1AttributeTests(MyFixture fixture)
    {
        this.fixture = fixture;
    }

    //...
}

[Collection("MyFixture Collection")]
public class MySecondTestClass
{
    private readonly MyFixture fixture;

    public ParallelCollectionMultiClass1AttributeTests(MyFixture fixture)
    {
        this.fixture = fixture;
    }

    //...
}